Teachers complained that they were viewed as beginners despite many years of classroom experience in their own countries.
Those arriving in the UK from the West Indies, South America and Africa (excluding South Africa) were less likely to receive higher pay in recognition of qualifications gained in their own countries than those from Europe, North America or Australia.
Two-thirds of teachers from African countries (not South Africa) and 60 per cent of those from India had job problems in the UK, the survey of 186 overseas teachers found.
South American and West Indian teachers were also more likely to have had periods out of work than other groups.
Staff complained that obtaining Qualified Teacher Status was time-consuming and degrading with little support offered. Some said they were not aware before arriving in the UK that they would be required to obtain the qualification before they would be able to receive the same pay as teachers trained domestically.
The NUT's survey is the latest sign of a growing concern about racism in schools.
A Brighton university study found that Britain's education system is institutionally racist, with pupils and teachers vulnerable to abuse.
Inspectors warned earlier this year that a quarter of councils are not doing enough top promote equal educational opportunities for pupils from all ethnic groups.
Trevor Phillips, chairman of the Commission for Racial Equality, has warned that the CRE will take schools to court if they fail to implement race equality plans.
A spokesman for the Teacher Training Agency said it would look closely at the NUT report.